§1.1 Field of the Invention
The present invention concerns finding items, such as advertisements (“ads”), relevant to a request, such as a search query. In particular, the present invention concerns helping to determine, score, and/or render an expanded set of relevant ads.
§1.2 Related Art
Advertising using traditional media, such as television, radio, newspapers and magazines, is well known. Unfortunately, even when armed with demographic studies and entirely reasonable assumptions about the typical audience of various media outlets, advertisers recognize that much of their ad budget is simply wasted. Moreover, it is very difficult to identify and eliminate such waste.
Recently, advertising over more interactive media has become popular. For example, as the number of people using the Internet has exploded, advertisers have come to appreciate media and services offered over the Internet as a potentially powerful way to advertise.
Advertisers have developed several strategies in an attempt to maximize the value of such advertising. In one strategy, advertisers use popular presences or means for providing interactive media or services (referred to as “Websites” in the specification without loss of generality) as conduits to reach a large audience. Using this first approach, an advertiser may place ads on the home page of the New York Times Website, or the USA Today Website, for example. In another strategy, an advertiser may attempt to target its ads to narrower niche audiences, thereby increasing the likelihood of a positive response by the audience. For example, an agency promoting tourism in the Costa Rican rainforest might place ads on the ecotourism-travel subdirectory of the Yahoo Website. An advertiser will normally determine such targeting manually.
Normally, when a member of the advertising audience (referred to as a “viewer” or “user” in the Specification without loss of generality) selects an ad by clicking on it, embedded hypertext links typically direct the viewer to the advertiser's Website. This process, wherein the viewer selects an ad, is commonly referred to as a “click-through” (“Click-through” is intended to cover any user selection). The ratio of the number of click-throughs to the number of impressions of the ad (i.e., the number of times an ad is displayed or otherwise rendered) is commonly referred to as the “click-through rate” or “CTR” of the ad.
A “conversion” is said to occur when a user consummates a transaction related to a previously served ad. What constitutes a conversion may vary from case to case and can be determined in a variety of ways. For example, it may be the case that a conversion occurs when a user clicks on an ad, is referred to the advertiser's Web page, and consummates a purchase there before leaving that Web page. Alternatively, a conversion may be defined as a user being shown an ad, and making a purchase on the advertiser's Web page within a predetermined time (e.g., seven days). In yet another alternative, a conversion may be defined by an advertiser to be any measurable/observable user action such as, for example, downloading a white paper, navigating to at least a given depth of a Website, viewing at least a certain number of Web pages, spending at least a predetermined amount of time on a Website or Web page, etc. Often, if user actions don't indicate a consummated purchase, they may indicate a sales lead, although user actions constituting a conversion are not limited to this. Indeed, many other definitions of what constitutes a conversion are possible. The ratio of the number of conversions to the number of impressions of the ad (i.e., the number of times an ad is displayed or otherwise rendered) is commonly referred to as the conversion rate. If a conversion is defined to be able to occur within a predetermined time since the serving of an ad, one possible definition of the conversion rate might only consider ads that have been served more than the predetermined time in the past.
The hosts of Websites on which the ads are presented (referred to as “Website hosts” or “ad consumers”) have the challenge of maximizing ad revenue without impairing their users' experience. Some Website hosts have chosen to place advertising revenues over the interests of users. One such Website is “Overture.com,” which hosts a so-called “search engine” service returning advertisements masquerading as “search results” in response to user queries. The Overture.com Website permits advertisers to pay to position an ad for their Website (or a target Website) higher up on the list of purported search results. If such schemes where the advertiser only pays if a user clicks on the ad (i.e., cost-per-click) are implemented, the advertiser lacks incentive to target their ads effectively, since a poorly targeted ad will not be clicked and therefore will not require payment. Consequently, high cost-per-click ads show up near or at the top, but do not necessarily translate into real revenue for the ad publisher because viewers don't click on them. Furthermore, ads that viewers would click on are further down the list, or not on the list at all, and so relevancy of ads is compromised.
Search engines, such as Google for example, have enabled advertisers to target their ads so that they will be rendered in conjunction with a search results page responsive to a query that is relevant, presumably, to the ad. Although search result pages afford advertisers a great opportunity to target their ads to a more receptive audience, search result pages are merely a fraction of page views of the World Wide Web. To increase advertising opportunities, some online advertising systems may use ad relevance information and document content relevance information (e.g., concepts or topics, feature vectors, etc.) to “match” ads to (and/or to score ads with respect to) a document including content, such as a Web page for example. The foregoing ad serving systems can be thought of as keyword-targeted systems (where ads are targeted using terms found in a search query) and content-targeted systems (where ads are targeted using content of a document).
The Google ad system allows advertisers to target their ads in a one or more ways so that the ads will likely be relevant, and therefore useful, when served. For example, currently, advertisers may target ads using one of three keyword matching methods: exact; phrase; and broad. With exact matching, the query must be identical to keyword targeting criteria (i.e., one or more words or phrases used to make a targeting judgment (e.g., to determine whether an ad is relevant or not)). With phrase matching, the query must contain the targeting criteria words in the order specified by the phrase. Finally, with broad matching, the query must contain any one of one or more of the targeting criteria keywords, in any order.
All three of these keyword matching methods use keyword targeting criteria. Keyword targeting criteria are normally provided by the advertiser as an explicitly entered list or lists. For example, an advertiser may enter a list of all words which might appear in a relevant search query. Although this approach permits the serving of highly relevant ads, and therefore ads which should perform well, it does have some limits. For example, advertisers might not be able to appreciate, or even foresee, search queries or search terms entered by a user who would be receptive to their ads. Therefore, it would be useful to provide more sophisticated ways of identifying ads that are relevant to a search query, even if the search query doesn't contain the exact words targeted by the advertiser. Therefore it might often be useful to relax the notion of relevant ads.